The overall program goal is to develop a safe, convenient, pure oxygen generator for lower cost in-home therapy by patients suffering from chronic obstructive pulmonary disease (COPD). The device will electrochemically convert water to high-purity humidified oxygen for breathing, using ambient air as a reactant. Successful development of the electrochemical oxygen generator could lead to a reduction in maintenance requirements resulting in lower annual costs for patients. The Phase I SBIR Program demonstrated the feasibility of a unique are- depolarized cathode structure specifically for use in a solid polymer electrolyte cell that operates at high current density in a water flooded environment. To date, no other cathode structure has been rugged enough to survive this harsh environment, limiting air-depolarized solid polymer electrolyte oxygen generators to short life and low current density operation. The Phase II program, advanced technologies will be evaluated to achieve higher current density operation through cathode optimization. Other aims of the program include developing unique design concepts leading to long life, maintenance free operation and low-cost materials. The advanced technologies and concepts will be refined and optimized in two-cell stack an da full-size 2 L/min 2 generator prototype.